Electric furnace.



J. WiBROWN. v ELECTRIC FURNACE. *A PPLIO ATIOK FILED JAILB, 1912.

I Patented Apr. 14, 19m

2 SHEETS-SHEET 1.

INVENTOR W v JQH/V WERQW/V Jfluw BY g y- ATTORN EV WITNESSES J. W. BROWN.-

ELECTRIC FURNACE. .ALPPLIGAT'ION' FILED JAN. 8,1912.

Patented Apr.14,191

INVENTOR EH/N W 5170 W WITNESSES BY ATTORNEY UNITED s'ratrns PATENT oFFIoE.

JOHN W. Brown, or LAKEWOOD, 01110, assrenon TO NATIONAL cannon COMPANY,

or CLEVELAND, 01110, A CORPORATION or NEW JERSEY.

ELECTRIC FURNACE.

Specification of Letters Patent.

Patented Apr. 14, 1914.

Application filed January 8, 1912. Serial No. 670,069.

' In electric furnaces heretofore used there has been a heavy loss of energy due to the "loss of heat through the furnace walls. Also it has heretofore been found necessary to USQWfl-tBI' pipes to cool the treated charge down to a temperature Where it can be taken out into the open' air, and not ruin the conveying apparatus. The heat absorbed by the water Was all lost. The old type of furnace therefore requires a continual heavy input of electr cal energy to maintain the high temperature and supply the losses, and a large and continuous supply of water. I

-I have designed a regeneratlve furnace that eliminates the greater part of the heat loss and the water consumption, and hence the furnace will operate at a great deal hi her efficiency than the usual type.

ther objects and advantages will appear in the following description, particular reference being had to the drawings in which: Figure 1 is a sectional elevation of a regenerativefurnace, being taken on the line BB of Fig. 2. Fig. 2 is a cross section taken in the line AA of Fig. 1. Fig. 3 is a sectional elevation of a part of a modified furnace. Fig. {l is a sectional elevation of another modification. Fig. 5 is a sectional elevation of a rotary type of regenerative furnace. Fig. 6 is a modified type of rotary furnace.

Referring to Fig. 1, the outer wall of'the furnace is indicated at 1. and may be constructed of firebrick, carborundum, or any other heat insulating material. The furnace is hexagonal in cross section as will be seen in referring to Fig. 2. The shape of the cross section is, however, immaterial as it could be of any shape. The furnace has a cover 2,which serves, to confine heat radiated upward and. the gases ,evolved and may also serve to support the upper carbon This electrode is adjusted through the cover as it is consumed. There is an inner wall 4- which may be of the same material and shape as the wall-1. Within the wall t is a carbon channel 5 through which the granular charge passes to the conveyer 6. The lower electrodes 7 are joined to the channel 5 and extend to the outside of the furnace through sleeves 8, leaving a space filled with a gasbetween the electrode and the sleeve. These sleeves or their equivalent are desirable if the outer walls are made of a conducting material such as carbon. However, if they are made of an insulating material such as carborundum 'or firebrick, the sleeves need not be used. The electrode 7 may be screwed into the channel 5 or connected in any manner to get a good contact, The granular charge is fed into the furnace through the hoppers 9, and is carried slowly upward in the channel between the walls 4: and l by means of a carrier 10 having small platforms 11. The conveyor is made in a manner well known in the art, and hence is not shown in detail. Motion is transmitted to the conveyer through gears 12 and 13 which may be furnishedwith power from any sourcesuch as a belt or an electric motor. A member 14: is adjusted in such manner as to tilt the platforms so that the charge will slide off. In this way the charge is worked to the top of the furnace, interrupting and absorbing heat being'radiated or conducted outward from the heating zone or heated material. The platforms are biased to the position perpendicular to the furnace wall.

By referring to Fig. 2 it will be seen that there are six conveyers, but the number is immaterial. Any number may be used that is desired.

The three lower electrodes are to be joined to a common bus bar. However, the furnace may be constructed to use less or more than three as the number is immaterial.

In the operation of my furnace, the charge in the vicinity of the ends of the electrodes becomes intensely heated and is converted to graphite. By adjusting the upper electrode and regulating the current by any means, the heating may be controlled so that a carbon product baked to any temperature below that of graphitization may be produced. The conveyer 6 slowly removes the graphite or other product from the bottom of the channel 5, consequently 110 the hot graphite moves away from the elecconveyed upward it will become more heated from the absorption of the heat from the treated charge. The untreated charge is thus continually receiving heat from the time it leaves the base of the furnace till it reaches the top. The treated charge is continually losing heat from the time it leaves the electric heating zone till it reaches the conveyer 6.

In practice the furnace wouldbe twenty five or thirty feet high so that therewill be sutficient time for the. graphite to cool by radiating, its heat to the untreated charge. The furnace could be made of any desired height.

It will be evident that this type of furnace will be very efficient since most of the heat is returned to the charge.

Fig. 3 illustrates a slightly different furnace. This is similar to that in Fig. 1- with the exception that the inner Wall 4 is omitted. v The operation of this type would be the same as that already described.

Fig. 4 illustrates another vertical type. Parts ofthe furnace that are similar to those in Fig. 1 are designated by the same reference character, and need not be further described. The charge is fed downward be tween the walls 1 and 4 through hoppers 15, and is forced upward to the heating region between the wall 4' and the channel 5. On account of the outer column being higher than theinncr one, there would be a tendency for the charge to flow through its own weight to the heating zone. However, other means would probably be desirable, and I have shown a ring 16 that is adapted to be reciprocated by any means such as two crank wheels 17 connected to the ring by jointed piston rods. A pulley 18 is shown for driving the mechanism. The reciprocating member need not be in the shape of a: ring. It may be formed into a plurality of independent plungcrs without changing the:

operation in the least. When the member 16 is forced upward the charge will move upward between the wall 4 and the channel 5 and when the member descends the material from the outer column will flow in to take its place. This is due to the outer col-- umn being of greater height and also to the shape of the spaces between the-walls. The

walls 1 and 4 leave a space bet ween them that is divergent downward while the space between the wall 4 and the channel 5 is divergent upward. Hence the charge would be continuously moved upward into the heating region even if the two columns were of the same height. This would be due to the fact that the outer column would offer a greater resistance to an upwardly directed force,

while the inner column would otter a greater resistance to a downwardly directed force.

The regenerative 'features described in re gard to Fig. 1 are also found in the mod1fication of F1". 4 and the i need not be a am a a .l mentioned.

The cross sectional form of the furnace in 'Fig. 4 is preferably circular though it may be limited to the particular type of elec' trodes shown in the foregoing figures, as.

the regenerative feature canbe used with various forms of electrodes wit it departing from the scope of the inventi The particular type is shown only foi the purpose of explanation.

The hoppers 15 may be either a series of hoppers at various places, around the circumference of the furnace, or a circular hopper may be placed around the top of the furnace.

Fig. 5 illustrates a rotary type of furnace in which 19 is the stationary base carrying supporting roller bearings 20 fastened to a driving axle 21, carrying the drivin pulley 22. The rotary part 23 is supported the set, of rollers or gears shownin the figure, and a similar set removed a small distance therefrom. The part 23 may be made of cast iron or steel, or of cast iron or steel lined with firebrick. A central channelis made up of a section 24 that' may be made of the same material as the part 23, and another section made of carbon. The two sections may be connected in any manner. The

entire central channel may be madc of carbon if desired. The sectionsare supported at various places by standards the lower row only being shown. An electrode 95 (}T\' tends through the end of the wall 25-3. A slip connection is made at 26 so that the current can be conveyed to the electrode. plurality of electrodes QT extend diamctri cally through the wall 233 and are connected by any means to the carbon cclion of the inside channel. slip connection 28 is made so that the current can be conveyed to the electrodes. The charge is fed thr ugh the stati nary hopper "l9. and as the furna e l rotated ii i. linnhlcd alongir ia-idually .thc Qlecti'ic heating zone throu 'h the t'tlll nd channel to the. outside at itl. 'lhc spiial etwcen The electrode 25 is adjustable and the space between the electrodes may be made smell so that an intense heat is produced It is obvious that this rotary type of furnace is regenerative in the same "manner as the vertical type. The roller bearings 29 are preferably corrugated so as to aid in turning the furnace, or they may be gears meshing in the teeth in the wall 23. The pulley or wheel 22 may I receive power from any source.

In Fig. 6 a slightly modified rotary type is shown. This difiers from Fig. 5 in having two centralelectrodes 25 and 32 inside the channel.- The electrode preferahly rc tates with the furnace, though it may he sta tionary and supported by a standard outside the furnace. A slip connection is diagrammatically represented at, 26. The electrode 32 1s preferably stationary. The central. channel is not one of the electrodes in this case. a The spiral corrugations are not shown in this modification, as I intend to construct furnaces'both with and without corrugations in the inside. The furnace in Fig. 6 is otherwise similar to that of Fig. 5, but not all the .common features are shown.

Having describedmy invention what 1' claim is:

1. The method of treating a granular conducting charge which consists in moving it in one direction as a heat absorbing envelop, then moving the advanced portions in the opposite direction within the incoming envelop and passing an electric current "through the material within said envelop.

2. The method of treating a granullar con ducting charge which consists in moving in one direction as a heat absorhing envelop then moving the advanced portions in the opposite direction within the incoming envelop and passing an electric current rcction and through the inner channel in the reverse direction.

5. In an electric furnace an outer channel, an intermediate channel, and inner channel, heating electrodes and means for moving the furnace charge successively through the said three channels in alternate directions.

6. an electric furnace, heating electrodes, an outer channeha l-intermediate channel, an inner channel, said first mentioned channel being divergent in one direction, and said second mentioned channel being divergent in the opposite direction, and

means for moving the furnace chargethrough the second channel.

7. In an electric furnace, heating electrodes, an outer channel, an intermediate channel, an inner channel, two of said channels being divergent in opposite directions and means for moving the furnace charge through one of the channels.

8. In an electric furnace, an inner shaft adapted to be completely filled with treated material, an outer concentric shaft adapted to be completely filled with material incompletely treated for absorbing the heat from the material in the inner shaft, and means for causing the material to pass successively through the shafts in opposite directions.

9. in an electric furnace, an upper electrode, a hollow lower electrode forming'an inner channel, an intermediate channel, an outer channel and means for moving the-furnacc charge successively through the said three channels in alternate directions.

10. In electric furnace of the vertical type, a plurality of concentric shafts, heating electrodes and means for moving the furnace charge through an outer shaft and in the opposite direction through an inner shaft.

11. In an electric furnace of the vertical shaft type, an upper electrode, a hollow lower electrode. an outer channel concentric to said lower electrod, means for passing' an envelop of material around the lower electrode, and within the outer inclosing channel whereby the untreated material is preheated. and means for removing the treated material from the hollow electrode.

.ln testimony whereof I have hereunto signed my name.

JOHN W. BROWN. Witnesses:

F. D. TAURENCE, R. H. H. Amer. 

